Traditionally, gratings used in industrial applications as walkways and the like have been made of steel. However, non-metallic gratings, particularly those made of fiberglass, have achieved great success in recent years. This success stems from a number of reasons. A fiberglass grating weighs far less than a steel grating. Many environments which would corrode steel have no effect on the fiberglass. Also, fiberglass gratings have great resiliency to absorb shock loading.
Typically a grating, whether steel or fiberglass, will be secured to a structural member by some clamping structure. The design of the fasteners becomes very critical when installing fiberglass gratings because of the particular properties of the fiberglass itself Many fasteners suitable for steel are unsatisfactory for fiberglass, because of its great flexibility.
Fibergrate Corporation, of Dallas, Tex., the assignee of all rights in the present invention, has developed a number of clips for mounting grates on structural members. For example, the type A hold-down clip uses a single U-shape clip with a fastener to mount one beam of a fiberglass grate to a structural member The type M hold-down clip has a double U-shape which simultaneously holds two adjacent beams to a structural member with a single fastener. Other fasteners available in the technology secure adjacent beams of a fiberglass grate, with each beam having a I-beam cross section including a base, to a structural member through the adjacent bases In one design, a wedge shaped member bears on the inner portion of the adjacent bases and is bolted directly to the structural member. In another design, the bases are required to have a flange which parallels the structural member and a bar acts on those flanges to fasten the grate to the structural member.
While several clamping systems available currently for non-metallic gratings are usable, occasionally the load bars of a fiberglass grating will spread or move apart under load when restrained by traditional clamps Therefore a need exists to develop a clamping system which is more compatible with the properties of the materials used in the gratings, particularly fiberglass, while minimizing the cost for the materials of the clamping system, and also minimizing the effort required to install the grate with the clamping system.